Enamel leather and process of making same.



NITEDV STATES Patented May 9,1905.

PATENT ()FFICE.

WILLIAM W. ADAMS, JR., OF PHILADELPHIA, AND HARRY C. MoKAY, OFESSINGTON, PENNSYLVANIA, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AMERICANPATENT KID COMPANY, A CORPORATION OF NEW JERSEY.

ENAMEL LEATHER AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 789,249, dated May 9,1905.

Application filed December 29,1900. Serial No. 41.453.

To all whom, it may concern:

Be it known that we, WILLIAM W. ADAMs, J r., residing at Philadelphia,and HARRY C. MGKAY, residing at Essington, Delaware county,Pennsylvania, citizens of the United States, have invented certain newand useful Improvements in Enamel Leather and Processes of Making theSame, of which the following is a full, clear, and exact description,referencebeing had to the accompanying drawings, forming a part of thisspecification.

Our invention relates to the manufacture of enamel and patent leathers;and it consists of a new and improved process or method of making suchleathers and of a new product as the result thereof.

It relates specifically to that class of such leathers in which theenameling is applied to the grain side of the skin and without anyprevious buffing thereof, and not to that class in which the enamelingis applied to the flesh side or to the grain side, which has beenrendered soft and porous by buffing. Hence our process is applicableparticularly to the manufacture of enamel and patent leathers fromgoatskins and other light leathers on which it is not desirable to applythe enamelilng to the flesh side nor to buff the grain SIC e.

Our improved process comprises two essential stepsnamely, the degreasingor extractingof all natural and applied grease from the tanned skin tobe enameled, followed by the application thereto of a preparatoryvarnish composed of a drying-oil, specifically, boiled linseed-oil and apyroxylin carrier thereof, which will be absorbed into and on the skintissues through and below the exterior hard grain-surface of the tannedskin.

An additional step in our process, which though not essential in allcases, as hereinafter stated, is frequently desirable, is the compactingand smoothing of the grain-surface prior to the application of thepreparatory varnish before mentioned.

In carrying out our process the tanned skins prepared to the point wherethey would otherwise be surface-finished in any of the various knownways to make them merchantable are treated as follows: The natural andapplied grease in the tanned skins or leather is completely extracted,for which purpose any of the well-known degreasing processes may beemployed-such, for example, as that in which a naphtha solvent is used asuitable one being described in United States Letters Patent to W. W.Adams, Jr. Nos. 685,551 and 685,552, both dated October 29, 1901. Thisdegreasing step is the first in our process and is absolutely essentialto enable the preparatory varnish, hereinafter described, to penetratethe grain side below the surface and to adhere to the fibers thereof.The next step in the process, which may, however, be employed beforedegreasing the tanned skin as aforesaid, is a smoothing and compactingof the grain, which may be done in any suitable way long familiar totanners and curriersfor example, by repeated manual application of aslicker with force over the surface or mechanically by giving the skinthe usual first treatment under the glass roller of a glazing-machine asthough the tanned skin was to be made into glazed kid, in which case ausual seasoning, such as a blood season, should be applied. Thissmoothing and compacting step is not, however, essential in all cases,as some skins naturally have and some tannages give a low smooth grain;but for the greater varieties of tanned goatskins such smoothing andcompacting will be very desirable for the production of perfectlysmooth-surfaced enamel and patent leathers of this class. The next stepin the process is the application to a tanned skin degreased, as firststated, and preferably in most cases with the fibers of its grain sidecompacted, as aforesaid, of a preparatory varnish composed of apyroxylin solution and boiled linseed-oil, dissolved in a solvent. ofboth, such as amyl acetate. This solution must have considerablefluidity, so as to be applied to the skin by a brush or sponge. It

will be absorbed by the fibrous structure of the grain side withoutproducing an enamel coating. Such effects are obtained by a mixturehaving such properties, resulting from boiling linseed-oil to theconsistency of fresh mucilage, thinning one quart of this with an equalbulk of amyl acetate or sufficient to give it a consistency of 31 Baum,and then adding a pyroxylin solution consisting of one pound ofguncotton in eight quarts of amyl acetate, and for a pigment and drieradding to every three gallons of this mixture a solution of one andone-half ounces of nigrosin in one quart of methyl alcohol. Such acomposition has great penetrating power. It will be absorbed almostinstantly by the skin so prepared, penetrating the exteriorgrain-surface and enveloping and adhering to the fibers composing thewhole epidermis or grain side of the skin, and forms a preliminarycoating so thin and transparent as to be scarcely perceptible, but soeffective for our purpose that the usual exterior enamel commonlyapplied in making patent-leather adheres so firmly thereto that apeeling or separation thereof after drying becomes impossible. Theremaining steps in the manufacture of our enamel and patent leathers areas follows, v'iz.: The tanned skins having been degreased, as aforesaid,and the grain smoothed or compacted, if need be, and then placed on theusual stretching-frames, are treated on the grain side by thepreparatory varnish above referred to, dried in the sun or in an oven,and finally treated while still on the frame by the application theretoof any well-known exterior enamel or varnish commonly applied in makingenamel and patent leathers.

In a separate application for patent filed by one of usHarry C. McKayonDecember 29, 1900, Serial No. 41,461, (on which Letters Patent N 0.704,082 were issued, dated July 8, 1902,) is described a specificpreparatory varnish of the character described, and hence adapted to beused with great utility in the carrying out of our new process.

Our invention in the process and in the resultant leather produceddifiers entirely as to both from the process and product described inthe United States patent to Field, No. 627,493, dated June 27, 1899, andequally so from the process and product described in the United Statespatents to VVolfl', Nos. 632,162 and 632,163, both datedAugust 29, 1899.In neither of these prior processes is the tanned skin prepared bysubjection to either of our preparatory steps, and in the former of themthe preparatory varnish employed is a solution of a pyroxylin compoundwith a nondrying oil, while in the Wolff process there is applied apreparatory varnish or enamel directly to the grain-surface of goatskinor kid-leather which will not be absorbed by Said surface, but will forman adherent flexible coating thereupon. Our process, however, isradically different from both of these in the two essential particularswhich distinguish it, since, first, we prepare the tanned skin todeprive it of its oil-resistant grease and make it more absorbent, and,second, we employ a preparatory varnish of the character described whichwill penetrate the grain side and envelop and adhere to the fiberscomposing the same. It is our experience that goatskins and kid-leatherfinally enameled on the grain side, especially when not previouslybuffed or roughened, will when submitted to a treatment by our process,as described, preliminary to the application of any usual externalenamel coating possess great flexibility and unusual freedom fromcrackingand peeling.

The enameled leather which is the product of our new process is exactlylike other kidleather in respect of its flesh side; but as to the grainside of the skin it differs therefrom in having the entire fibrousstructure thereof enveloped by the preparatory varnish which forms aflexible film-like covering of the fibers, attaching itself thereto withremarkable adherence and at the same time being so thin and transparentin character as scarcely to be perceptible, and hence not hiding theexternal grain texture of the skin and with the advantage thatfrequently we are able to make an excellent enamel leather with but asingle outside coating of the usual exterior enamel commonly employed,showing through the same the contour of the natural grain of the skin.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is-

1. An improved process of preparing unbufied tanned skins for enamelingwith the usual surface enamels, which consists in first extracting fromthe skin its contained natural and applied grease, then applying to theunbuffed grain sideof the skin the described pyroxylin solution andboiled linseed-oil dissolved in a solvent of both, whereby a thin,transparent and flexible coating is formed upon and adheres to thefibrous structure constituting the grain side of the skin.

2. An improved process of enameling unbuffed tanned skins, whichconsists in compacting and smoothing the unbuffed grain side thereof,then extracting the natural and applied grease from the skin, thenapplying the described pyroxylin and boiled linseed-oil solution wherebyan adhering, thin, flexible and transparent coating is formed upon thegrain side, and, after drying, finally applying upon said grain side anyusual exterior surface enamel.

3. As a new article of manufacture, enameled leather composed of tannedskin from which the natural and applied grease has been extracted, andhaving upon and throughout IIO- the fibrous structure constituting itsgrain side, a thin, flexible and transparent coating resulting from theemployment of a pyroxylin solution with linseed-oil, of the characterdescribed, said coating penetrating the fibrous structure of theunbuffed grain side of the skin and forming a homogeneous uniontherewith, and an exterior adherent surface enamel superposed thereon.

In testimony whereof we have hereunto affixed our signatures this 26thday of December, A. D. 1900.

WILLIAM W. ADAMS, JR. HARRY O. MoKAY.

Witnesses:

ANDREW V. GRoUPE, H. T. FENTON.

